Does altitude have any effect on model/shading/anything?

[Anonymous]

Hey team

This is my first post and as I couldn't find this info anywhere I'm starting a new topic.

I just received a topographical survey for a new project from the surveyor and the levels are not in relation to a known vertical datum (sea level) bur rather to an assumed level of 10m (a benchmark he established and attributed the 10m to). The survey is obviously still fine and I can model my mesh normally but the actual altitude of the site is around 82m above sea level.

I've been using Archicad for 2 years now and this is the first time I received a survey without the sea level datum since.... My question is: will the "wrong" altitude affect shading or anything else in the model? Or is it completely irrelevant in that regard and only longitude and latitude matter?

I thought of importing Google Earth terrain (have never done it before) for this project as there is a significant hill on the eastern side of the section that has not been surveyed and will affect morning sun so having that slope modeled would be beneficial. When the GE terrain is imported, do you assign elevation to it yourself?

Would appreciate any input
Thanks guys

[Barry Kelly]

I don't honestly know the answer, but I doubt the datum of your survey will have any affect on shadows in the model.
The only time that the shadows will be affected by elevation (height) is if you are doing a sun study at the exact time the sun would be dipping below the horizon.
So your adjacent hill will have an effect on the very early morning sun (shadows).
But as to the accuracy of those shadows with the sun at such a low angle, I don't think I would be relying on Archicad for the correct results.
An approximation yes but not for certain accuracy.


As for your terrain, you can set the altitude of your model in the location settings.
You create the mesh (based on the survey) and you can elevate it to the correct height as you want it.
The only thing that may be wrong is the spot height and contour level text in the survey - but they can be changed if you need to.


Barry.

[Anonymous]

Thank you Barry

As for your terrain, you can set the altitude of your model in the location settings.
You create the mesh (based on the survey) and you can elevate it to the correct height as you want it.
The only thing that may be wrong is the spot height and contour level text in the survey - but they can be changed if you need to.

That was sort of my worry, yes... As I only have approximate real altitude information from basically one spot height taken from geoplaner.com (82m), I wouldn't be able to properly assign new "real" levels to the contour lines because they'll certainly be off. I won't be able to pin down a datum height correctly either so that will be no help for the builder.

I will keep things as they are, good to know it doesn't somehow throw off shading.

Thank you for your time Barry, much appreciated